The standard laser oscillator configuration, as in FIG. 1, has several disadvantages for high power operation:
a. A Maltese cross pattern is produced when the laser is Q-switched. This can be partially corrected by placing a half wave plate between two rods, but this requires an extra component and puts some operational limitations on the system.
b. Stress birefringence in the rod causes a substantial loss in efficiency. This can be corrected by inserting the rejected polarization back into the beam with another dielectric polarizer, but this requires several extra components including an extra dielectric polarizer which has a high susceptibility to damage.
c. Losses due to stress birefringence in the pockels cell or incomplete Q-switching cannot be recovered.
d. Losses of a few percent per pass by reflection of the polarization that should be transferred through the dielectric polarizer cannot be recovered.
The present invention eliminates all four of the above drawbacks in the standard configuration, and has some additional advantages.